I have a 1950s home and it started to smell like poop in the basement. It didn't overflow, I see the water, but when the cap is off the smell is terrible.

There's a hole in the concrete floor where the sewage/waste cleanout is and an old cast iron plug that's 1/4"-3/8" too big for the hole so it just sits on top (from whoever left it).

I've gone to big box stores and bought a 3 1/2" and 4" cleanout plug, and the same sizes for expandable test plugs.

The cast iron pipe area I cleaned out with a screw driver and a tooth brush, and I don't see any threads (large or small).

The 4" sizes are roughly 1/4" too big and the 3 1/2" would fall through.

Is there any other option just to plug it even if temporarily so I'm not breathing this in for days to come?

I used a plastic container to sit on top, weighted down, and I placed plywood on top of the hole to seal it temporarily but it is not effective.


1 Answer 1


First, measure the OUTSIDE diameter of the cast iron pipe where this opening is. Then go to the hardware store and by a Fernco coupler of the appropriate size. The coupler is basically a short tube made of rubber, with hose clamps.

You'll also need a PVC threaded cleanout fitting, and a cleanout cap. Pick the size of that based on the Fernco couplers available to you at the hardware store.

  • Thanks so much for replying. I actually bought a 4" flexible pipe cap with the clamp but of course, it was near/the exact size of the total diameter of the pipe. I haven't found one larger than 4". My other issue is the majority of the pipe I have clamping space but the pipe goes to the right where there's maybe an inch or less of space to clamp on to, so I'm not sure if this will work. I'm currently looking at a cleanout adapter fitting but it's not as snug given it'd just sit on top. Oct 26, 2018 at 19:05
  • @VictorBureau - you may have to go to a plumbing supply place instead of a big-box store. Bring them pictures with exact measurements - they'd be able to hook you up. Might cost you more, but it will smell nicer!
    – FreeMan
    Oct 26, 2018 at 19:09
  • Franco makes several cap sizes but the big box stores don't usually carry them where a specialty plumbing store may and they are usually glad to order the correct one if they don't have it in stock.+
    – Ed Beal
    Oct 26, 2018 at 19:24

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